remove_empty_ps.php

remove-empty-ps.php

<?php
/**
 * Remove Empty Ps
 *
 * Deletes empty <p> tags on save.
 * This can be included as a standalone plugin.
 */

namespace Gist\EmptyPs;

/**
 * Kick off all the things.
 */
function bootstrap() {
	add_action( 'save_post', __NAMESPACE__ . '\\save_p_less_content', 10, 3 );
	add_filter( 'the_content', __NAMESPACE__ . '\\remove_empty_ps' );
}

/**
 * When a post is saved, remove any empty <p> tags (or anything that would result in empty <p>
 * tags, like carriage returns which render as &nbsp; in the database).
 *
 * @uses   remove_empty_ps We use the remove_empty_ps function again in here after running the
 *                         content through wpautop so we can scrape out empty lines.
 * @param  int    $post_id The WP_Post ID.
 * @param  object $post    The WP_Post object.
 * @param  bool   $update  Whether this is an update.
 */
function save_p_less_content( $post_id, $post, $update ) {
	if ( wp_is_post_revision( $post ) || in_array( $post->post_type, [ 'attachment' ], true ) ) {
		return;
	}

	// Remove the empty <p> tags by running the content through `wpautop` to wrap &nbsp;'s in <p>s.
	$post_content = remove_empty_ps( wpautop( $post->post_content ) );

	// Build up the new post.
	$updated_post['ID']           = $post_id;
	$updated_post['post_content'] = wp_kses_post( $post_content );

	/*
	 * Danger, Will Robinson!
	 *
	 * Calling wp_update_post inside save_post has the potential to create an infinite loop.
	 * To solve this connundrum, we're un-hooking this function from save_post to prevent it from
	 * running when wp_update_post is run. We don't need to re-hook it, since we already hooked it
	 * in bootstrap().
	 */
	remove_action( 'save_post', __NAMESPACE__ . '\\save_p_less_content', 10, 3 );
	wp_update_post( $updated_post );
}

/**
 * This deals with empty blocks particularly on output and especially caused by shortcodes wrapped
 * in <p> and <div> tags.
 *
 * @link                   https://gist.github.com/ninnypants/1668216
 * @param  string $content The post content.
 * @return string          The filtered post content.
 */
function remove_empty_ps( $content ) {
	// Clean up <p> tags around block elements.
	$content = preg_replace(
		[
			'#<p>\s*<(div|aside|section|article|header|footer)#',
			'#</(div|aside|section|article|header|footer)>\s*</p>#',
			'#</(div|aside|section|article|header|footer)>\s*<br ?/?>#',
			'#<(div|aside|section|article|header|footer)(.*?)>\s*</p>#',
			'#<p>\s*</(div|aside|section|article|header|footer)#',
		], [
			'<$1',
			'</$1>',
			'</$1>',
			'<$1$2>',
			'</$1',
		],
		$content
	);

	return preg_replace( '#<p>(\s|&nbsp;)*+(<br\s*/*>)*(\s|&nbsp;)*</p>#i', '', $content );
}

// Engage!
bootstrap();